Genetic differentiation in Zeiraphera diniana (Lepidoptera: Tortricidae, the larch budmoth): polymorphism, host races or sibling species?

Abstract

Eleven larch-and pine-feeding populations of the larch budmoth were studied in Western Europe using 24 allozyme loci. Hierarchical F-statistics between larch and pine forms (FSTO.O65) were much greater than those between localities within larch (FSTO.0O2) and within pine (FST 0.026), even when sympatric host-associated populations were considered.Analysis of Nei's genetic distance produced similar results, and a UPGMA tree of all populations consistently clustered samples from the same hosts together. Three loci, autosomal Pgm and Mdh-s and sex-linked Idh-s, were the most important loci involved in differences between the two forms. Previously considered to be conspecific, it is now clear that the larch and pine biotypes of Z. diniana are either host races (sensu Diehi & Bush, 1984) or good sympatric species which hybridize rarely. Regardless of taxonomic status, the distribution of larch and pine in the Pleistocene, phenological differences between the two hosts, together with the great vagility of Z. diniana, an outbreak pest, suggest that sympatric or parapatric differentiation is at least as likely as allopatric divergence.

The maintenance of species differences across a Heliconius hybrid zone

“…Most allozyme data sets show a few significant deviations from Hardy-Weinberg equilibrium (e.g. Mallet et al, 1993;Emelianov et al, 1995) but, if there is no consistent pattern across loci or populations, these Fig. 1 Neighbour-joining tree of Heliconius himera and three races of H. erato.…”

“…The thorax and abdomen of each individual was homogenized on ice in 80 RL of grinding buffer (Mallet et at., 1993;Emelianov et at., 1995). The homogenate was centrifuged to remove cellular debris.…”

“…Plates were run with samples of both species in order to ensure accurate scoring of alleles between runs. Plates were stained according to recipes described elsewhere (Mallet et at., 1993;Emelianov et at., 1995). the 3' end of the cytochrome oxidase subunit I (COl) gene, the leucine tRNA gene and most of the cytochrome oxidase subunit II (COIl) was amplified using primer sequences 5'-CCATAATAAATTC-CAGGYCGGTTAA-3' and 5'-GAAATATTATTT-CCTCTTYFGGATCC-3'.…”

Host-plant-associated genetic differentiation in Northern French populations of the European corn borer

“…The theory that new species may evolve despite gene flow has recently gained theoretical support (Schluter, 1998;Tregenza and Bridle, 1998;Dieckmann and Doebeli, 1999;Kondrashov and Kondrashov, 1999;Kirkpatrick and Ravigné, 2002) and has been accompanied by an increasing number of examples of sympatric host races (eg Emelianov et al, 1995;Via, 1999;Groman and Pellmyr, 2000). The influence of ecological factors in speciation has also recently been emphasized (Schluter, 1998;Schilthuizen, 2000;Via, 2001).…”

“…Host-associated genetic differentiation has already been documented in other moth families such as the Noctuidae (Pashley, 1986), Tortricidae (Emelianov et al, 1995) and Prodoxidae (Groman and Pellmyr, 2000). Populations of O. nubilalis differ in terms of pheromone blends (E vs Z) and voltinism (uni-vs bivoltine) (Hudon et al, 1989).…”